MYOSIN AUTOANTIBODIES DETECTED BY IMMUNOFLUORESCENCE

  • 1 January 1977
    • journal article
    • research article
    • Vol. 28  (1) , 27-34
Abstract
Autoantibodies to striated and smooth muscle myosins were detected by indirect immunofluorescence and confirmed by absorption with purified contractile proteins extracted from human, rabbit and chicken muscle. Myosin antibodies were rare: of 55 sera examined from patients with various skeletal and cardiac muscle disorders, only 1 serum, from a case of Coxsackie viral pericarditis, had antimyosin activity. It reacted with cardiac muscle and type 1 fibers of skeletal muscle, staining only the A band of the sarcomere. The antibody was absorbed by skeletal myosin and by skeletal heavy meromyosin fragments, but not by smooth muscle myosin. Two types of myosin smooth muscle autoantibodies (SMA) are described. One is restricted to smooth muscle myosin and examples were found in polyclonal and monoclonal SMA sera. The 2nd type of myosin SMA cross-reacted with skeletal and cardiac muscle and with cytoplasmic myosin in liver, kidney and thyroid cells. It was completely absorbed by smooth or skeletal myosin and by heavy meromyosin fragments. The different types of myosin autoantibodies reflect the variety of myosins found in mammalian tissues. Cross-reacting myosin antibodies indicate epitopes on the heavy meromyosin fragment which are common to several different tissue myosins.